There would not be.
Example:
Stand on a scale and put a cup of water at your feet.
Tie a string around a rock and hold it.
Note the weight.
Allow the rock to dip into the water.
The scale will remain unchanged.
Negative bouyancy only means than an object will sink if not suspended. It is not an added force that needs to be considered, especially considering that the steel ball is externally supported and negative bouyancy can not apply as a result.
Your example would reflect the ball being suspended from the bucket, not the ground.
...I promise I'll get the hang of replying in the right spot...
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That's fair, but the result is the same either way. No additional forces to consider.
Since it is supported by the ground, all downward force is applied to the ground and not to its side of the system.
